Modern agricultural planters typically utilize a pair of discs which rotate together and cut into the soil as they are drawn across the ground to form a furrow. Seed is then deposited into the furrow at regular, spaced intervals and then the furrow is closed over the seed for germination to begin. As depicted in FIGS. 1A and 1B, the standard practice of closing the furrow F over the seeds S is to utilize a pair of press wheels W. These press wheels are drawn behind the seed depositing mechanism and straddle the furrow, with one wheel on each side of the furrow and normally angled inwardly at the bottom where the wheel contacts the ground immediately adjacent the furrow. As the press wheels are drawn along the furrow, they press the sides of the furrow together, closing it over the deposited seed. These standard press wheels are often less than satisfactory in some soil conditions. For example, in soil with a high clay content the furrow walls can be so tightly compacted together as to form an impenetrable barrier over the germinating seed.
In recent years, a new approach called no-till farming has been introduced wherein the fields are planted without first tilling the previous crop. The presence of the stubble and residue from the previous crop substantially reduces the loss of water from the soil and also greatly reduces erosion. However, this residue can have an adverse affect on the planting by interfering with the action of the furrow forming discs and the furrow closing press wheels. Devices are being developed which are attached to the planter ahead of the furrow cutting discs and function to chop up and clear the residue and debris to facilitate the action of the furrow forming discs and the furrow closing devices.
While these row cleaning devices are quite effective, the residue and debris still interfere somewhat with the press wheels. U.S. Pat. No. 5,443,023 to this inventor discloses a furrow closing device which utilizes a pair of tine wheels in place of the standard press wheels. As depicted in FIGS. 2A and 2B, as these tine wheels are drawn adjacent the seed furrows, the tines are able to penetrate the residue and debris to better enable furrow closure. Furthermore, the side walls of the furrows and the adjacent soil are fragmented as the furrow is closed, preventing excessive soil compaction. However, even this improvement was less than satisfactory in loose or sandy soil. In those situations, the soil was overly fragmented and therefore suffered an excessive loss of moisture.